Technical Abstract:
Insect growth regulators (IGRs) are insecticides that mimic insect-produced hormones that regulate the developmental process. They generally have little or no mammalian toxicity, and are considered reduced-risk insecticides that are often exempt from tolerance requirements of regulatory agencies. Although IGRs have been available for more than 30 years, there is increased interest and application for stored-product pest control. Insect growth regulators can be used for direct application to stored grains, and worldwide perhaps the most common IGR used for this purpose is methoprene. Within the last few years, there has been new research showing that this IGR is very effective against Rhyzopertha dominica (Coleoptera: Bostrichidae), one of the most destructive pests of stored grain worldwide. However, one of the limitations of IGRs is that they generally do not kill adult insects. Recent studies show that the addition of methoprene to diatomaceous earth (DE), a natural product, or a contact insecticide will give complete control of this species on stored grains. Another application of IGRs is as surface treatments to flooring structures of mills, warehouses, and processing plants. Hydroprene (Gentrol) is particularly effective against late-instars of Plodia interpunctella (Lepidoptera: Pyralidae), Tribolium castaneum and T. confusum (Coleoptera: Tenebrionidae). Other IGRs that are effective against these insects when used as surface treatments are methoprene and pyriproxyfen. The final category where IGRs can be used in pest management programs is as aerosol spray treatments. In the United States, there are a number of facilities that have integrated methoprene aerosols into their control programs. The use of IGRs can easily be integrated into pest management strategies to control stored-product insects in bulk grain and in milling, processing, and storage facilities.